Executive cognitive function (ECF) refers to a cluster of cognitive processes that facilitate goal-directed mental phenomena such as selective attention, self-control, and complex problem solving and is largely localized to the prefrontal cortex. ECF is an important predictor of multiple obesity-related health behaviors such as high calorie/low nutrient food intake, sedentary behavior, and physical activity, and has been repeatedly linked to childhood obesity outcomes. Independent lines of evidence from across the lifespan increasingly suggest that near-roadway air pollution (NRAP) may be both neurotoxic and linked to the development of childhood obesity. Though multiple pathways have been proposed to explain the link between NRAP and childhood obesity, little work to date has explored the role ECF may play in mediating the relationship to obesity-related behaviors and obesity. To investigate longitudinal relationships between children's exposure to NRAP and both childhood obesity outcomes and obesity-related behavior, mediated by ECF, this proposal will leverage pre-existing resources from multiple NIH-funded studies. Specifically, we propose to assign NRAP exposures to residential and school addresses of a large cohort of children who have been followed longitudinally in the Pathways to Health (Pathways) dataset, using CALINE4 source dispersion models developed for the Southern California Children's Health Study. Linear mixed effects models will then be utilized to examine longitudinal associations between functional neurocognitive deficits and air pollution exposure in Pathways from 4th through 6th grade- which evidence suggests constitutes a critical period of prefrontal cortical vulnerability. Finally, a multilevel structural equation modeling approach will be utilized to determine to what degree the relationship between air pollution exposure and two obesity outcomes (body mass index percentile and waist circumference) and obesity-related behaviors (e.g. sedentary behavior, physical activity, high-calorie/low-nutrient food consumption and fruit/vegetable consumption) is mediated by ECF changes, adjusting for key covariates, including participants' perceived stress, smoking history and sleep patterns.